iOS使用CoreData实现收藏功能

　　一般做收藏都是使用数据库或者归档,使用CoreData实现收藏功能就是没事时练一下,实现大概和数据库差不多.

首先创建一个工具类继承NSObject,在里面实现所需要的方法.

　　工具类的.h文件:

typedef NS_ENUM(NSUInteger, SelectInEntities) {
    InEntities,
    NotInEntities,
    SelectError,
};

typedef NS_ENUM(NSUInteger, Entities) {
    NewsEntity,
    PostEntity,
    TypeEntity,
    ForumEntity,
};

@interface BFFCoreDataManager : NSObject

// 管理对象上下文(管理者)
@property (readonly, strong, nonatomic) NSManagedObjectContext *managedObjectContext;
// 管理对象模型(表结构)
@property (readonly, strong, nonatomic) NSManagedObjectModel *managedObjectModel;
// 持久化存储协调器(助理)
@property (readonly, strong, nonatomic) NSPersistentStoreCoordinator *persistentStoreCoordinator;
// 保存上下文(保存对数据的修改)
- (void)saveContext;
// 沙盒路径
- (NSURL *)applicationDocumentsDirectory;

//-(SelectInEntities)isInEntities:(Entities)entities
//                    Model:(id)model;

+(BFFCoreDataManager *)shareBFFCoreDataManager;

- (id)isInEntities:(Entities)entities model:(id)model;
+ (BOOL)has:(NSMutableDictionary *)dic arr:(NSArray *)array;
///地方分会
+ (BOOL)hass:(NSMutableDictionary *)dic arr:(NSArray *)array;
///推荐论坛
+ (BOOL)hasss:(BFFDiscussModel *)model arr:(NSArray *)array;
+ (BOOL)haspost:(BFFSelectModel *)model arr:(NSArray *)array;
+ (BOOL)state:(NSArray *)arr url:(NSString *)url;
+ (BOOL)states:(NSArray *)arr ids:(NSString *)ids;

- (id)myModel:(id)model;
@property (nonatomic, strong) BFFCoreDataManager *manager;

@end
    工具类的.m文件

@implementation BFFCoreDataManager
#pragma mark - Core Data stack

@synthesize managedObjectContext = _managedObjectContext;
@synthesize managedObjectModel = _managedObjectModel;
@synthesize persistentStoreCoordinator = _persistentStoreCoordinator;

+ (BFFCoreDataManager *)shareBFFCoreDataManager
{
    /// 单例不能释放
    static BFFCoreDataManager *manager = nil;
    // 保证线程安全, 该方法只走一次
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        manager = [BFFCoreDataManager new];
    });
    return manager;

}

// 获取到沙盒的Document路径

- (NSURL *)applicationDocumentsDirectory {
    // The directory the application uses to store the Core Data store file. This code uses a directory named "com.lanou3g.TheWorldCar" in the application's documents directory.
    return [[[NSFileManager defaultManager] URLsForDirectory:NSDocumentDirectory inDomains:NSUserDomainMask] lastObject];
}

- (NSManagedObjectModel *)managedObjectModel {
    // The managed object model for the application. It is a fatal error for the application not to be able to find and load its model.
    if (_managedObjectModel != nil) {
        return _managedObjectModel;
    }
    NSURL *modelURL = [[NSBundle mainBundle] URLForResource:@"TheWorldCar" withExtension:@"momd"];
    _managedObjectModel = [[NSManagedObjectModel alloc] initWithContentsOfURL:modelURL];
    return _managedObjectModel;
}

- (NSPersistentStoreCoordinator *)persistentStoreCoordinator {
    // The persistent store coordinator for the application. This implementation creates and returns a coordinator, having added the store for the application to it.
    if (_persistentStoreCoordinator != nil) {
        return _persistentStoreCoordinator;
    }
    
    // Create the coordinator and store
    
    _persistentStoreCoordinator = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel:[self managedObjectModel]];
    NSURL *storeURL = [[self applicationDocumentsDirectory] URLByAppendingPathComponent:@"TheWorldCar.sqlite"];
    NSError *error = nil;
    NSString *failureReason = @"There was an error creating or loading the application's saved data.";
    
    NSDictionary *options = [NSDictionary dictionaryWithObjectsAndKeys:[NSNumber numberWithBool:YES], NSMigratePersistentStoresAutomaticallyOption, [NSNumber numberWithBool:YES], NSInferMappingModelAutomaticallyOption, nil];
    
    if (![_persistentStoreCoordinator addPersistentStoreWithType:NSSQLiteStoreType configuration:nil URL:storeURL options:options error:&error]) {
        // Report any error we got.
        NSMutableDictionary *dict = [NSMutableDictionary dictionary];
        dict[NSLocalizedDescriptionKey] = @"Failed to initialize the application's saved data";
        dict[NSLocalizedFailureReasonErrorKey] = failureReason;
        dict[NSUnderlyingErrorKey] = error;
        error = [NSError errorWithDomain:@"YOUR_ERROR_DOMAIN" code:9999 userInfo:dict];
        // Replace this with code to handle the error appropriately.
        // abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development.
        NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
        abort();
    }
    
    return _persistentStoreCoordinator;
}

- (NSManagedObjectContext *)managedObjectContext {
    // Returns the managed object context for the application (which is already bound to the persistent store coordinator for the application.)
    if (_managedObjectContext != nil) {
        return _managedObjectContext;
    }
    
    NSPersistentStoreCoordinator *coordinator = [self persistentStoreCoordinator];
    if (!coordinator) {
        return nil;
    }
    _managedObjectContext = [[NSManagedObjectContext alloc] initWithConcurrencyType:NSMainQueueConcurrencyType];
    [_managedObjectContext setPersistentStoreCoordinator:coordinator];
    return _managedObjectContext;
}

#pragma mark - Core Data Saving support

- (void)saveContext {
    NSManagedObjectContext *managedObjectContext = self.managedObjectContext;
    if (managedObjectContext != nil) {
        NSError *error = nil;
        if ([managedObjectContext hasChanges] && ![managedObjectContext save:&error]) {
            // Replace this implementation with code to handle the error appropriately.
            // abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development.
            NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
            abort();
        }
    }
}

- (id)myModel:(id)model{
    NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
    NSEntityDescription *entity = [NSEntityDescription entityForName:@"Type" inManagedObjectContext:self.managedObjectContext];
    [fetchRequest setEntity:entity];
    NSError *error = nil;
    NSArray *fetchedObjects = [self.managedObjectContext executeFetchRequest:fetchRequest error:&error];
    if (fetchedObjects == nil) {
        NSLog(@"%@", error);
    }
    BFFCollectModel *newsModel = model;
    for (Type *type in fetchedObjects) {
        if ([type.name isEqualToString:newsModel.name]) {
            return type;
        } else {
            return nil;
        }
    }

return nil;
}

// 判断是否在数据库中
- (id)isInEntities:(Entities)entities model:(id)model
{
    switch (entities) {
        case NewsEntity:
        {
            NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
            NSEntityDescription *entity = [NSEntityDescription entityForName:@"News" inManagedObjectContext:self.managedObjectContext];
            [fetchRequest setEntity:entity];
            NSError *error = nil;
            NSArray *fetchedObjects = [self.managedObjectContext executeFetchRequest:fetchRequest error:&error];
            if (fetchedObjects == nil) {
                NSLog(@"%@", error);
            }
            BFFNewsModel *newsModel = model;
            for (News *news in fetchedObjects) {
                if ([news.newsLink isEqualToString:newsModel.newsLink]) {
                    return news;
                }
            }
            return nil;
        }
            break;
        case PostEntity:
        {
            NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
            NSEntityDescription *entity = [NSEntityDescription entityForName:@"Post" inManagedObjectContext:self.managedObjectContext];
            [fetchRequest setEntity:entity];
            NSError *error = nil;
            NSArray *fetchedObjects = [self.managedObjectContext executeFetchRequest:fetchRequest error:&error];
            if (fetchedObjects == nil) {
                NSLog(@"%@", error);
            }
            BFFHotModel *hot = model;
            for (Post *post in fetchedObjects) {
                if ([post.postLink isEqualToString:hot.postLink]) {
                    return post;
                }
            }
            return nil;
        }
            break;
        case TypeEntity:
        {
           
        }
            break;
        case ForumEntity:
        {
            NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
            NSEntityDescription *entity = [NSEntityDescription entityForName:@"Line" inManagedObjectContext:self.managedObjectContext];
            [fetchRequest setEntity:entity];
            NSError *error = nil;
            NSArray *fetchedObjects = [self.managedObjectContext executeFetchRequest:fetchRequest error:&error];
            if (fetchedObjects == nil) {
                NSLog(@"%@", error);
            }
            BFFCarDetailModel *carDetail = model;
            for (Line *line in fetchedObjects) {
                if ([line.seriesId isEqualToString:[NSString stringWithFormat:@"%@", carDetail.seriesId]]) {
                    return line;
                }
            }
            return nil;
        }

break;
        default:
            break;
    }
    return nil;
}
///爱车俱乐部.人车生活
+ (BOOL)has:(NSMutableDictionary *)dic arr:(NSArray *)array{
    NSNumber *num = dic[@"forumId"];
    for (Forum *forum in array) {
        if ([forum.postId isEqualToString:num.description]) {
            return YES;
        }
    }
    return NO;
}
///地方分会
+ (BOOL)hass:(NSMutableDictionary *)dic arr:(NSArray *)array{
    NSNumber *num = dic[@"id"];
    for (Forum *forum in array) {
        if ([forum.postId isEqualToString:num.description]) {
            return YES;
        }
    }
    return NO;
}
///论坛推荐
+ (BOOL)hasss:(BFFDiscussModel *)model arr:(NSArray *)array{
    for (Forum *forum in array) {
        if ([forum.postId isEqualToString:model.forumId.description]) {
            return YES;
        }
    }
     return NO;
}
///帖子收藏
+ (BOOL)haspost:(BFFSelectModel *)model arr:(NSArray *)array{
    for (Post *post in array) {
        if ([post.postLink isEqualToString:model.postLink]) {
            return YES;
        }
    }
    return NO;
}
///改变帖子收藏按钮图标
+ (BOOL)state:(NSArray *)arr url:(NSString *)url{
    for (Post *post in arr) {
        if ([post.postLink isEqualToString:url]) {
            return YES;
        }
    }
    return NO;
}
///改变论坛收藏按钮图标
+ (BOOL)states:(NSArray *)arr ids:(NSString *)ids{
    for (Forum *forum in arr) {
        if ([forum.postId.description isEqualToString:ids]) {
            return YES;
        }
    }
    return NO;
}

//-(SelectInEntities)isInEntities:(Entities)entities
//                          Model:(id)model
//{
//    switch (entities) {
//        case NewsEntity:
//        {
//            NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
//            NSEntityDescription *entity = [NSEntityDescription entityForName:@"News" inManagedObjectContext:self.managedObjectContext];
//            [fetchRequest setEntity:entity];
//            NSError *error = nil;
//            NSArray *fetchedObjects = [self.managedObjectContext executeFetchRequest:fetchRequest error:&error];
//            if (fetchedObjects == nil) {
//                NSLog(@"%@", error);
//            }
//            BFFNewsModel *newsModel = model;
//
//            for (News *news in fetchedObjects) {
//
//                if ([news.newsLink isEqualToString:newsModel.newsLink]) {
//                    return InEntities;
//                } else {
//                    return NotInEntities;
//                }
//
//            }
//
//        }
//            break;
//            case PostEntity:
//        {
//
//        }
//            break;
//            case LineEntity:
//        {
//
//        }
//            break;
//            case ForumEntity:
//        {
//
//        }
//            break;
//        default:
//            break;
//    }
//    return SelectError;
//}
@end
  接下来在收藏页面创建一个Button实现收藏

- (void)collectionBut:(id)sender{

BFFCollectModel *model = self.tempModel;
    if ([self.manager myModel:model] == nil) {
       Type *type = [NSEntityDescription insertNewObjectForEntityForName:@"Type" inManagedObjectContext:self.manager.managedObjectContext];
        type.name = model.name;
        type.priceRange = model.priceRange;
        type.photo = model.photo;
        type.uid = [NSString stringWithFormat:@"%@", model.uid];
        [self.manager saveContext];
        
        self.collectLabel.text = @"已经收藏";
        self.collectLabel.hidden = NO;
        dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(0.5 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
            self.collectLabel.hidden = YES;
        });
        
        
    } else {
        [self.manager.managedObjectContext deleteObject:[self.manager myModel:model]];
        [self.manager saveContext];
        self.collectLabel.text = @"已取消收藏";
        self.collectLabel.hidden = NO;
        dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(0.5 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
            self.collectLabel.hidden = YES;
        });
    }
}
在我的收藏页面把数据取出

- (void)createLineData
{
    self.typeArr = [NSMutableArray array];
    NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
    NSEntityDescription *entity = [NSEntityDescription entityForName:@"Type" inManagedObjectContext:self.manager.managedObjectContext];
    [fetchRequest setEntity:entity];
    NSError *error = nil;
    NSArray *fetchedObjects = [self.manager.managedObjectContext executeFetchRequest:fetchRequest error:&error];
    
    if (fetchedObjects == nil) {
        NSLog(@"%@", error);
    }
    [self.typeArr addObjectsFromArray:fetchedObjects];
    [self.tableView reloadData];
    
}
这些数据都铺在了tableView上接下来实现删除的操作

- (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath
{
    if (editingStyle == UITableViewCellEditingStyleDelete) {
        if (self.titleSegment.selectedSegmentIndex == 0) {
            News *news = self.newsArr[indexPath.row];
            [self.manager.managedObjectContext deleteObject:news];
            [self.manager saveContext];
            [self.newsArr removeObjectAtIndex:indexPath.row];
            [self.tableView deleteRowsAtIndexPaths:@[indexPath] withRowAnimation:UITableViewRowAnimationLeft];
        }else if (self.titleSegment.selectedSegmentIndex == 1){
            Post *post = self.postArr[indexPath.row];
            [self.manager.managedObjectContext deleteObject:post];
            [self.manager saveContext];
            [self.postArr removeObjectAtIndex:indexPath.row];
             [self.tableView deleteRowsAtIndexPaths:@[indexPath] withRowAnimation:UITableViewRowAnimationLeft];
        }else if (self.titleSegment.selectedSegmentIndex == 2){
            Forum *forum = self.forumArr[indexPath.row];
            [self.manager.managedObjectContext deleteObject:forum];
            [self.manager saveContext];
            [self.forumArr removeObjectAtIndex:indexPath.row];
            [self.tableView deleteRowsAtIndexPaths:@[indexPath] withRowAnimation:UITableViewRowAnimationLeft];

}else{
        
            Type *type = self.typeArr[indexPath.row];
            [self.manager.managedObjectContext deleteObject:type];
             [self.manager saveContext];
            [self.typeArr removeObjectAtIndex:indexPath.row];
            [self.tableView deleteRowsAtIndexPaths:@[indexPath] withRowAnimation:UITableViewRowAnimationLeft];
        
        }
    }
    [self.tableView reloadData];
}
      这些就是实现收藏的过程